package com.lan.springframework.beans.factory.support;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

import com.lan.springframework.beans.BeansException;
import com.lan.springframework.beans.PropertyValue;
import com.lan.springframework.beans.PropertyValues;
import com.lan.springframework.beans.factory.DisposableBean;
import com.lan.springframework.beans.factory.InitializingBean;
import com.lan.springframework.beans.factory.config.AutowireCapableBeanFactory;
import com.lan.springframework.beans.factory.config.BeanDefinition;
import com.lan.springframework.beans.factory.config.BeanPostProcessor;
import com.lan.springframework.beans.factory.config.BeanReference;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;

/**
 * @author Keason
 * @version 创建时间：2022年11月19日 下午12:02:01
 * @TODO
 * 
 */
public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFactory implements AutowireCapableBeanFactory {
	 private InstantiationStrategy instantiationStrategy = new CglibSubclassingInstantiationStrategy();

	    @Override
	    protected Object createBean(String beanName, BeanDefinition beanDefinition, Object[] args) throws BeansException {
	        Object bean = null;
	        try {
	            bean = createBeanInstance(beanDefinition, beanName, args);
	            // 给 Bean 填充属性
	            applyPropertyValues(beanName, bean, beanDefinition);
	            // 执行 Bean 的初始化方法和 BeanPostProcessor 的前置和后置处理方法
	            bean = initializeBean(beanName, bean, beanDefinition);
	        } catch (Exception e) {
	            throw new BeansException("Instantiation of bean failed", e);
	        }

	        // 注册实现了 DisposableBean 接口的 Bean 对象
	        registerDisposableBeanIfNecessary(beanName, bean, beanDefinition);

	        registerSingleton(beanName, bean);
	        return bean;
	    }

	    protected void registerDisposableBeanIfNecessary(String beanName, Object bean, BeanDefinition beanDefinition) {
	        if (bean instanceof DisposableBean || StrUtil.isNotEmpty(beanDefinition.getDestroyMethodName())) {
	            registerDisposableBean(beanName, new DisposableBeanAdapter(bean, beanName, beanDefinition));
	        }
	    }

	    private Object initializeBean(String beanName, Object bean, BeanDefinition beanDefinition) {
	        // 1. 执行 BeanPostProcessor Before 处理
	        Object wrappedBean = applyBeanPostProcessorsBeforeInitialization(bean, beanName);

	        // 执行 Bean 对象的初始化方法
	        try {
	            invokeInitMethods(beanName, wrappedBean, beanDefinition);
	        } catch (Exception e) {
	            throw new BeansException("Invocation of init method of bean[" + beanName + "] failed", e);
	        }

	        // 2. 执行 BeanPostProcessor After 处理
	        wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
	        return wrappedBean;
	    }

	    private void invokeInitMethods(String beanName, Object bean, BeanDefinition beanDefinition) throws Exception {
	        // 1. 实现接口 InitializingBean
	        if (bean instanceof InitializingBean) {
	            ((InitializingBean) bean).afterPropertiesSet();
	        }

	        // 2. 注解配置 init-method {判断是为了避免二次执行初始化}
	        String initMethodName = beanDefinition.getInitMethodName();
	        if (StrUtil.isNotEmpty(initMethodName) && !(bean instanceof InitializingBean)) {
	            Method initMethod = beanDefinition.getBeanClass().getMethod(initMethodName);
	            if (null == initMethod) {
	                throw new BeansException("Could not find an init method named '" + initMethodName + "' on bean with name '" + beanName + "'");
	            }
	            initMethod.invoke(bean);
	        }
	    }

	    private void applyPropertyValues(String beanName, Object bean, BeanDefinition beanDefinition) {
	        try {
	            PropertyValues propertyValues = beanDefinition.getPropertyValues();
	            for (PropertyValue propertyValue : propertyValues.getPropertyValues()) {

	                String name = propertyValue.getName();
	                Object value = propertyValue.getValue();

	                if (value instanceof BeanReference) {
	                    // A 依赖 B，获取 B 的实例化
	                    BeanReference beanReference = (BeanReference) value;
	                    value = getBean(beanReference.getBeanName());
	                }
	                // 属性填充
	                BeanUtil.setFieldValue(bean, name, value);
	            }
	        } catch (Exception e) {
	            throw new BeansException("Error setting property values：" + beanName);
	        }
	    }

	    protected Object createBeanInstance(BeanDefinition beanDefinition, String beanName, Object[] args) {
	        Constructor constructorToUse = null;
	        Class<?> beanClass = beanDefinition.getBeanClass();
	        Constructor<?>[] declaredConstructors = beanClass.getDeclaredConstructors();
	        for (Constructor ctor : declaredConstructors) {
	            if (null != args && ctor.getParameterTypes().length == args.length) {
	                constructorToUse = ctor;
	                break;
	            }
	        }
	        return getInstantiationStrategy().instantiate(beanDefinition, beanName, constructorToUse, args);
	    }

	    public InstantiationStrategy getInstantiationStrategy() {
	        return instantiationStrategy;
	    }

	    public void setInstantiationStrategy(InstantiationStrategy instantiationStrategy) {
	        this.instantiationStrategy = instantiationStrategy;
	    }

	    @Override
	    public Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName) throws BeansException {
	        Object result = existingBean;
	        for (BeanPostProcessor processor : getBeanPostProcessors()) {
	            Object current = processor.postProcessBeforeInitialization(result, beanName);
	            if (null == current) return result;
	            result = current;
	        }
	        return result;
	    }

	    @Override
	    public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName) throws BeansException {
	        Object result = existingBean;
	        for (BeanPostProcessor processor : getBeanPostProcessors()) {
	            Object current = processor.postProcessAfterInitialization(result, beanName);
	            if (null == current) return result;
	            result = current;
	        }
	        return result;
	    }
}
